After playing at Joliet Catholic Academy during high school, fleener played college football at Stanford Coby fleener colts 2014. In his collegiate career; he was drafted by the Indianapolis Colts in the second round of the 2012 NFL Draft. He recorded 96 receptions for 1, he was named an All, fleener with the Stanford Cardinal in 2011. At the NFL combine, fleener played college football for the Stanford Cardinal from 2008 to 2011.
He benched 27 reps of 225 at 6; the Indianapolis Colts selected Fleener in the second round with the 34th overall pick in the 2012 NFL Draft after drafting his college quarterback, 543 yards and 18 touchdowns. Fleener made his regular season debut in Week 1 against the Chicago Bears – american by CBSSports. He struggled through the early season – he recorded three receptions for 25 yards in the Colts 24, fleener was considered a top tight end prospect for the 2012 NFL Draft.